A giant asteroid will make a flyby of Earth over the next few days, and armchair astronomers can watch the action live on their computers.

The near-Earth asteroid 4179 Toutatis, which is about 3 miles (5 kilometers) wide, will zoom within 4.3 million miles (7 million kilometers) of Earth during its closest approach early Wednesday morning (Dec. 12). That's too far away to pose any impact threat on this pass, but close enough to put on a pretty good show through top-notch telescopes, researchers say.

And some of those scopes will be tracking Toutatis' movements for the benefit of skywatchers around the world. The online Slooh Space Camera and Virtual Telescope Project, for example, will both stream live, free footage of the asteroid from professional-quality observatories.

Slooh will webcast Toutatis views from a scope in the Canary Islands off the west coast of Africa beginning at 3 p.m. EST (2000 GMT) today (Dec. 11). Another show will follow at 10 p.m. EST tonight (0300 GMT Wednesday), with footage from an instrument in Arizona. You can watch them at Slooh's website:

ASTEROID FLYBY: Newly-discovered asteroid 2012 XE54 is flying through the Earth-Moon system today approximately 230 thousand km (0.6 LD) from Earth. The space rock is about 36 meters wide, a little smaller than the Tunguska impactor that leveled 800 square miles of Siberian forest in 1908. Using a remote-controlled telescope in New Mexico, astronomers Ernesto Guido and Nick Howes photographed 2012 XE54 streaking among the stars on Dec. 11th:

Guido and Howes dedicate this image to the memory of their longtime friend and colleague Giovanni Sostero.

This asteroid will not hit Earth, but it is close enough, and thus bright enough, for amateur astronomers to track using backyard telescopes. When Guido and Howes photographed it this morning, it was shining at magnitude +13.

Astronomers monitoring the asteroid might have noticed an unusual eclipse during the early hours of Dec. 11th. According to calculations made by P. Tricarico, 2012 XE54 "will likely cross the Earth's shadow, causing a partial eclipse of the asteroid a few hours before reaching its minimum distance with the Earth. Asteroids eclipsing during an Earth flyby are relatively rare, with the first known case of asteroid 2008 TC3 which was totally eclipsed just one hour before entering Earth's atmosphere over Sudan in 2008, and asteroid 2012 KT42 experiencing both an eclipse and a transit during the same Earth flyby in 2012."

^ Witnesses who actually saw the object stated that it changed course a few times, before the explosion.

As the body neared the ground (forest), the bright body seemed to smudge, and then turned into a giant billow of black smoke, and a loud knocking (not thunder) was heard, as if large stones were falling, or artillery was fired. All buildings shook. At the same time the cloud began emitting flames of uncertain shapes.

It also left considerable radiation behind. (sound like an ice & rock comet ?)

After the event, the skies were lit up at night for days, hundreds of miles away.

At around 7:17 a.m. local time, Evenks natives and Russian settlers in the hills northwest of Lake Baikal observed a column of bluish light, nearly as bright as the Sun, moving across the sky.

^ Witnesses who actually saw the object stated that it changed course a few times, before the explosion.

As the body neared the ground (forest), the bright body seemed to smudge, and then turned into a giant billow of black smoke, and a loud knocking (not thunder) was heard, as if large stones were falling, or artillery was fired. All buildings shook. At the same time the cloud began emitting flames of uncertain shapes.

It also left considerable radiation behind. (sound like an ice & rock comet ?)

After the event, the skies were lit up at night for days, hundreds of miles away.

At around 7:17 a.m. local time, Evenks natives and Russian settlers in the hills northwest of Lake Baikal observed a column of bluish light, nearly as bright as the Sun, moving across the sky.

Draw your own conclusions.

How do we know it left radiation behind? We didn't even know what radiation was back then. Also, when you have tons of fine particles suspended in the air, it will reflect light. We've seen this happen with volcanic ash during huge eruptions.

And, "a column of bluish light" sure sounds like a fireball to me, after all, the blue is the hottest part of the flame.